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US 5,647,051 AGranted
Cold therapy system with intermittent fluid pumping for temperature control
AssigneeSeabrook Medical Systems, Inc.
InventorCharles S. Neer
Life of this patent
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AssigneeSeabrook Medical Systems, Inc.
InventorCharles S. Neer
Estimating the term…
A cold therapy system for applying a cooling pad to an area of the body of the user. The system comprises a portable insulated cooler having a lid and serving as a reservoir for water and ice. A pump is located within a housing affixed to the exterior of the cooler. The pump has an inlet operatively connected to the reservoir through the adjacent cooler wall. The pump has an outlet connected by an insulated delivery tube to the inlet of a pad. The outlet of the pad is connected by an insulated return tube, through the cooler wall to which the pump housing is affixed, to the reservoir. The pump is provided with a pulse-width modulating circuit having an electronic switch output that switches an intermittent drive current to the pump motor according to any one of a number of predetermined operating modes selectable by the operator through the use of a manual switch. Each of the operating modes provides the pad with a predetermined and repeatable temperature by altering the operating duty cycle of the drive current to the motor, the drive current being a combination of a medium fixed frequency pulse train having a fixed duty cycle and a very low fixed frequency DC pulse having a variable pulse width. The intermittent running of the pump motor further results in a compressive massaging effect by the pad.
A control system for the electric motor of a fluid pump, said control system comprising an electric DC motor, a source of DC current, a first astable multivibrator having a continuous first output signal at a fixed duty cycle, a second astable multivibrator operating at a frequency lower than said first astable multivibrator and at a fixed period and having a second output signal at a selectable duty cycle, an output transistor having an input in communication with each of said first and second output signals, said output transistor providing a third output signal to drive said motor when both said first and second output signals are simultaneously in a state to turn on said transistor, said fixed duty cycle determining the speed at which said motor runs and said selectable duty cycle determining the amount of time said motor runs per period of said selectable duty cycle.
A control system for determining the flow rate of water in a water-circulating cold therapy device of the type comprising a reservoir containing ice and water, a pump and an electric DC drive motor therefor, a pump inlet connected to said reservoir, a waterproof cold therapy application pad having an inlet and an outlet and a path for water therein connecting said pad inlet and outlet, a pump outlet, an insulated delivery tube connecting said pump outlet and said pad inlet, an inlet port in said reservoir, and an insulated return tube connecting said pad outlet and said reservoir inlet, said control system comprising a source of DC current for said pump motor, a first astable multivibrator having a continuous first output signal at a fixed duty cycle, a second astable multivibrator operating at a frequency lower than said first multivibrator and at a fixed period and having a second output signal at a selectable duty cycle, an output transistor having an input in communication with each of said first and second output signals, said output transistor providing a third output signal to drive said motor when both said first and second output signals are simultaneously in a state to turn on said transistor, said fixed duty cycle determining the speed at which said motor runs and said selectable duty cycle determining the amount of time said motor runs per period of said selectable duty cycle.
A method of controlling the flow rate of water in a water-circulating cold therapy device of the type comprising a reservoir containing ice and water, a pump and a DC electric drive motor therefor, a pump inlet connected to said reservoir, a waterproof cold therapy application pad having an inlet and an outlet and a path for water therein connecting said pad inlet and outlet, a pump outlet, an insulated delivery tube connecting said pump outlet and said pad inlet, an inlet port in said reservoir, an insulated return tube connecting said pad outlet and said reservoir inlet, and a source of DC current for said pump, said control method comprising the steps of connecting said source of current to a first astable multivibrator providing a continuous first output signal at a fixed duty cycle, connecting said source of current to a second astable multivibrator operating at a frequency lower than said first astable multivibrator and at a fixed period and providing a second output signal at a selectable duty cycle, providing an output transistor having an input in connection with each of said first and second signals, said transistor providing a third output signal when both said first and second output signals are simultaneously in a state to turn on said transistor, using said third output signal to drive said pump motor at a speed less than its maximum speed using said fixed duty cycle to determine said pump motor speed and using said selectable duty cycle to determine the amount of time said pump motor runs per period of said selectable duty cycle.
Dependencies are inferred from the claim text.